1. Field of the Invention
This invention relates to a jumper cable to interconnect two batteries and to indicate if the polarity is correct. The invention also provides an indication if one of the batteries has an internal short circuit or an open circuit cell within the battery. The invention also relates to a jumper cable that eliminates the chance of accidental arcing near either of the batteries involved in the jumping or boosting process.
2. Description of the Related Art
In the past several configurations of jumper cables have been developed to enable the user to start a vehicle with a low battery by utilizing another battery more fully charged. The problems sought to be overcome have been convenience and safety. Previous attempts to solve these problems have resulted in various devices.
Richard L. Zapf U.S. Pat. No. 4,272,142 on June 9, 1981 describes a jumper cable with a red and green light and a set of diodes to limit current flow to indicate if the clamps were not secured to the proper battery terminals.
C. Anthony Farque U.S. Pat. No. 4,349,774 on Sept. 14, 1982 describes a apparatus for use with a jumper cable which is said to allow attachment to the battery terminals without regard to polarity of the terminals. The device is described as utilizing a circuit that activates the two terminal blocks and establishes proper polarity only when the contacts within the blocks when are properly aligned by turning the blocks relative to each other. The device uses a diode bridge and logical AND gates along with a solenoid as part of the circuit of the apparatus.
Wayne L. Millhimes U.S. Pat. No. 4,386,818 on June 7, 1983 describes a polarity indicating connector for battery jumper cables. The connector provides a two state LED device with a green light to indicate proper polarity and a red light to indicate improper polarity.